For centuries, scientists have been trying to develop alive brick or building material that can detect structural damage, heal it automatically and respond to toxic chemicals present in the environment. Living concrete has immense potential as it has the ability to sustain even in harsh environmental conditions (i.e. scorching deserts, other planets like Mars, etc.). Cyanobacteria are very important for building alive bricks; they capture the sunlight via photosynthesis.
So far, scientists have developed a brick capable of reproducing and healing the cracks. Crack self-healing has become possible because the building blocks were added into the bacterial solution to keep them alive to make more later on. To build a living concrete, cyanobacteria is added to the mixture of warm water, sand and nutrients. The microbes present in the solution capture sunlight and spark the reaction that produces the calcium carbonate, and this results in gradually cementing the sand particles. Although this process is very slow, researchers are working on making it faster and self-efficient.
Dr. Srubar has worked with a food ingredient, i.e. gelatin; when it is dissolved in water and cooled down, it forms a special bond between the molecules. In addition to this, it can be used to a moderate temperature that is favourable for the growth of the bacteria. Moreover, he suggested gelatin could be a potential molecule to strengthen the matrix built by the cyanobacteria. When the gelatin was dissolved in the bacteria solution, the mixture was poured into moulds and cooled in a refrigerator. What they observed was that the gelatin formed its bonds — are more structured and grew faster and stronger. The shape of the formed concrete blocks depends on the molds that are used ( two-inch cube, shoebox-size blocks, etc.). The strength of the concrete varies — from a person to stand-on to use it for real construction work. Although the brick material is weak compared to most conventional concretes. When the bricks were stored in relatively dry air at room temperature, the blocks reached their maximum strength in a few days, and the bacteria gradually died. But even after a few weeks, the blocks are still alive. When bricks were again exposed to high temperature and humidity, many of the bacterial cells perk back up.
If we placed the half- cut-brick in a warm beaker with more raw materials and poured it into a mold. The process started again and begin concrete formation new. Each block has the capability to spawn three new generations, yielding eight descendant blocks. Now scientists are excited to utilise the reproductive ability of live building materials to aid construction in remote or austere environments.
The blocks can be made from a variety including virgin sand that comes from rivers, lakes and oceans. Dr. Srubar said waste materials like ground glass or recycled concrete can be used. The researchers’ team is working to make the material more practical for use by making the concrete stronger — For that, it is required to increase the bacteria’s resistance to dehydration, reconfigure the materials that can be flat-packed and easily assembled, like slabs of drywall; and susbstituiting cyanobacteria that doesn’t require the addition of a gel.
In one of the interviews, Dr. Srubar quotes enthusiastically, “There’s no way we’re going to carry building materials to space, we’ll bring biology with us.”